1. Field of the Invention
The present invention relates to a tire driving stiffness measuring apparatus and a tire driving stiffness measuring method as well as a calculation method for prediction of fuel consumption using measured tire driving stiffness.
2. Description of the Related Art
Conventionally, a tire tester has been used, which carries out a performance test for a tire without actually mounting it to a vehicle so as to evaluate performance of the tire as a component of the vehicle (for example, see JP 1114225 B and JP 2002-148150 A. Meanwhile, an evaluation of fuel consumption by the cycles of the regulated drive of a vehicle is carried out on a vehicle where a tire is actually mounted, by using a measurement value obtained from a chassis dynamometer by applying a load equivalent to an actual running resistance.
Running resistance (force) generally consists of an air resistance (force) component and a mechanical resistance (force) component. It is understood that mechanical resistance (force) component chiefly includes rolling resistance (force) (RR). Thus, it has been considered that to reduce rolling resistance (force) (RR) of a tire serves as the most effective means for contributing to enhancement of fuel efficiency of a vehicle.
However, as results from careful analyses regarding contribution to fuel consumption of a tire, it has turned out that enhancement of tire driving stiffness serves for enhancing fuel efficiency as effectively as reduction of rolling resistance (coefficient) (RRC: rolling resistance coefficient). In addition, it has been turn out that fuel consumption of a tire could be predicted by using driving stiffness of the tire, as accurately as measuring fuel consumption of the tire actually mounted on a vehicle.
The present invention has an object to provide a tire driving stiffness measuring apparatus and a tire driving stiffness measuring method, as well as a calculating method for prediction of fuel consumption by using tire driving stiffness, as highly accurate as measuring fuel consumption of the tire actually mounted on a vehicle.